Technical Field of the Disclosure
The present invention relates to flexible wing shaping, and more particularly to using propulsion distributed along the wing to propel the vehicle and change wing shape.
Description of the Prior Art
The Wright brothers who invented the first aircraft realized the advantages of shape changing bird wings in flight control. They designed a wing warping flight control system to warp a wing by cables to change aircraft directions.
In modern time, NASA had developed a shape changing wing technology in the 1980's under the Mission Adaptive Wing program, which demonstrated a variable camber technology on the F-111 aircraft. The variable camber design allows the wing shape to change in order to adapt to different missions.
A NASA program in the early 2000's called Active Aeroelastic Wing developed a method for elastically shape a flexible wing to perform roll control. The concept is based on using leading edge slats and ailerons to twist highly modified flexible wings of an F-18 aircraft to generate differential lift for roll control.
In recent years, the Boeing 787 aircraft employs a light-weight, flexible wings that can flex substantially during flight. During certification testing, the wings flexed 25 ft upward under a proof load of 150% of the design load.
The NASA Helios prototype is an ultra-lightweight flying wing aircraft with a wingspan of 247 ft. A slight upward twist at the tips of the trailing edge helps prevent wing tip stalls during slow landings and turns. The flying wing aircraft is assembled in six sections, each about 41 ft long. A series of propellers are mounted at the joints of the wing panels. An underwing pod is attached at each panel joint to carry the landing gear, the battery power system, flight control computers, and data instrumentation.
To turn the Helios aircraft in flight, yaw control is applied by applying differential power on the motors—speeding up the motors on one outer wing panel while slowing down motors on the other outer panel. A major test during the initial flight series was the evaluation of locally varying motor power as a means of pitch control. During normal cruise the outer wing panels of Helios are arched upward and give the aircraft the shape of a shallow crescent when viewed from the front or rear. This configuration places the motors on the outer wing panels higher than the motors on the center panels. Speeding up the outer-panel motors caused the aircraft to pitch down and begin a descent. Conversely, applying additional power to the motors in the center panels caused Helios to pitch up and begin climbing.